Pathology in the subtalar joint can be debilitating, difficult to diagnose, and can lead to significant loss of time for the athlete. Subtalar instability is becoming more recognized in association with lateral ankle instability and also as an isolated source of “giving way” in the athlete. We try to elucidate some recent advancements in this sometimes-confusing area. Sinus tarsi syndrome has been a common complaint in the past and we try to update our readers regarding how to diagnose this syndrome and how to differentiate it from other forms of subtalar pathology. Tarsal coalitions often are symptomatic in the athlete. Although the coalition is found in approximately 2% of the population, the athlete often becomes symptomatic with its presence.

Anatomy

The subtalar joint is comprised of three articulating surfaces, referred to as the posterior facet, the middle facet, and the anterior facet. The bony articulations provide inherent stability and soft tissues provide additional stabilization. The lateral soft-tissue stabilizers have been classified into three separate layers.[1] The superficial layer is composed of the lateral root of the inferior extensor retinaculum, the lateral talocalcaneal ligament, and the calcaneofibular ligament. The intermediate layer consists of the intermediate root of the inferior extensor retinaculum and the cervical ligament. The deep layer consists of the medial root of the inferior extensor retinaculum and the interosseous talocalcaneal ligament ( Fig. 15-1 ).

The joints move in a triaxial plane, which allows for the motions of flexion/extension, inversion/eversion, and adduction/abduction.

The sinus tarsi is a space on the lateral aspect of the foot that lies anterior to the posterior facet between the talus and the calcaneus. It is in continuity with the tarsal canal. The tarsal canal is a cone-shaped opening within the subtalar joint and is situated in a posteromedial-to-anterolateral direction. Soft tissues within the sinus tarsi include the artery of the tarsal canal, bursae, nerve endings, and multiple ligaments.

Subtalar Instability

The role that instability of the subtalar joint plays in the patient with lateral ankle instability has been elucidated only recently. It has been estimated that 10% to 30% of patients with functional ankle instability, that is, patients that have pain, swelling, or a sense of “giving way” of the ankle, have evidence of instability of the subtalar joint. [0020] [0030] Some have suggested that consideration should be given to the concept of global hindfoot instability rather than simply functional instability about the ankle joint.[4]

Instability of the subtalar joint was first described in 1962 by Rubin and Whitten.[5] They proposed a series of stress radiographs to further evaluate this disorder. Brantigan et al.[6] were the first to detect radiographic evidence of subtalar instability in their series of three patients. Chrisman and Snook[7] in 1969 were able to document clinical subtalar instability in three of seven patients who were undergoing their tendon transfer procedure for lateral instability. Clanton and Berson[8] described subtalar injuries as a continuum of other injuries in athletes, particularly sprains of the lateral ankle ligaments.

Clinical presentation

The typical injury that leads to instability of the subtalar joint is a severe supination or supination-inversion force applied to the hindfoot. This results in a progressive injury to the talonavicular ligament and talonavicular capsule, followed by injury to the calcaneofibular and lateral talocalcaneal ligaments.[8] The presenting complaint often is a sensation of giving way of the ankle. The patient may report pain localized to the region of the sinus tarsi. Athletic activities can exacerbate the symptoms, resulting in a dependence on bracing or taping. Uneven surfaces may cause pain and a feeling of instability.

It is difficult to differentiate lateral ankle instability from subtalar instability on the basis of patient history. A thorough clinical and radiographic workup can help define the source of the athlete's complaints, but the differentiation still can be elusive.

Physical examination

The most notable finding on physical examination is increased inversion of the subtalar joint. This should be compared with the presumably uninjured opposite limb. The increased inversion can result from subtalar instability or a combination of subtalar and ankle instability. [0040] [0080] It is extremely difficult to detect the location of increased inversion by examination. In addition to increased inversion of the hindfoot, an increased translation of the calcaneus in the medial direction has been noted by Thermann et al.[9] In their study, a valgus stress was applied to the calcaneus, followed by an abrupt internal rotation stress. Results showed a medial shift of the calcaneus in relation to the talus or an opening of the talocalcaneal angle in patients with subtalar instability.

Following an acute injury, there may be swelling, bruising, and tenderness laterally. In the more chronic setting, increased inversion and lateral tenderness are more likely. It is easier to detect instability in the chronic setting because the athlete will be less apt to guard because of pain.

Radiographic evaluation

The initial radiographic workup of the patient with subtalar instability involves a weight-bearing anterior-posterior, lateral, and mortise view of the affected ankle, as well as weight-bearing anterior-posterior, lateral, and oblique radiographs of the affected foot to rule out evidence of bony pathology.

Pearl

When possible, obtain weight-bearing radiographs to assess the bony articulations under physiologic stress.

Plain radiographs often are negative, and further investigation must be carried out to arrive at the diagnosis. There have been multiple investigations into the use of stress radiographs in the workup of subtalar instability ( Fig. 15-2 ). [0060] [0100] [0110] [0120] In a series of three patients, Brantigan et al.[6] were able to radiographically demonstrate subtalar instability. They attributed the instability to an injured calcaneofibular ligament. Heilman et al.[12] sequentially sectioned ligaments in cadaver limbs and then obtained lateral and Broden's radiographs. They found that sectioning of the calcaneofibular joint caused a 5-mm opening of the subtalar joint. With subsequent sectioning of the interosseous ligament, the joint opened up to 7mm.

The usefulness of stress radiographs has come into question by multiple authors. [0130] [0140] [0150] Harper[13] reported a wide range of subtalar tilt with stress radiographs in his group of asymptomatic patients. Louwerens et al.[14] examined 33 patients with chronic ankle instability and 10 control patients who were asymptomatic. Broden's views were checked under fluoroscopy and they detected no difference between symptomatic and asymptomatic feet with regard to subtalar tilt or medial shift. Van Hellemondt et al.[15] examined both stress radiographs and stress computed tomography (CT) scans in 15 patients with unilateral chronic ankle instability with suspected subtalar instability. Although three of the symptomatic feet and one of the asymptomatic feet had increased subtalar tilt on plain films, there was no significant difference between the symptomatic and asymptomatic sides. None of the patients had increased subtalar tilt on the stress CT scans. The authors therefore doubted that a Broden's stress examination reveals the true amount of subtalar tilt.

In an acute injury, the usual treatment regimen for lateral ankle sprains will suffice for subtalar ligamentous injuries, as well. Rest, ice, compression, and elevation (RICE) are part of a good protocol, as well as immobilization and physical therapy, when needed. The same can be said for management of chronic subtalar instability. The routine nonoperative regimen used for chronic lateral ankle instability is initiated. This may include proprioceptive training, peroneal strengthening, and bracing or strapping. [0080] [0160] With bracing, it is important to understand the delicate balance in providing an athlete with enough support without impeding his or her performance. Taping by an athletic trainer before participation can be effective. Wilkerson[17] examined a modification of the standard method of ankle taping with the incorporation of a “subtalar sling.” He found that addition of the sling enhances the protective function of taping but cautioned that it may impede performance of certain activities.

Surgical treatment

Patients with residual symptomatic instability despite an adequate program of nonoperative management will require a surgical stabilization of their subtalar joint. If both ankle and subtalar instability exist and require surgery, both problems should be corrected at the time of surgery.[4] Surgical stabilization involves direct ligament repair or tendon transfers to substitute for the irreparable ligaments.

A less invasive technique that, according to Clanton and Berson[8] and Gould et al.,[22] provides a good treatment for subtalar instability is the Brostrom-Gould reconstruction technique for lateral ankle instability ( Fig. 15-3, D and E ). With the reconstruction of the calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) buttressed by the inferior extensor retinaculum, subtalar stability is effectively restored. [0080] [0220]

Sinus Tarsi Syndrome

Symptoms of sinus tarsi syndrome may overlap with those associated with subtalar instability. Some authors consider this syndrome simply a variant of subtalar instability.[27] Sinus tarsi syndrome describes pain localized to the region of the sinus tarsi. Characteristic findings on clinical and radiographic examination have not been well defined. Likewise, the pathologic changes found at the time of surgery are unclear. The most widely reported description of the pathologic anatomy associated with this condition is degenerative changes to the soft tissues of the sinus tarsi. [0280] [0290] The majority of cases are posttraumatic in nature but also may be related to inflammatory arthropathies, gout, ganglion cysts, and structural foot abnormalities. [0300] [0310]

Clinical presentation

The typical complaint is pain over the lateral and anterolateral ankle and hindfoot centered in the region of the sinus tarsi. The patient may report a sensation of mild hindfoot instability. It has been estimated that as many as 70% of patients with sinus tarsi syndrome have had a previous inversion injury to the hindfoot.[32]

Physical examination

Tenderness over the lateral ankle and hindfoot overlying the sinus tarsi is the most common finding on clinical examination. Patients may have findings of mild subtalar instability; however, this is difficult to elicit and often absent. Swelling overlying the sinus tarsi is variably present.

Radiographic evaluation

Plain films often are negative in this condition. Stress views may reveal mild subtalar instability, but, as stated in the previous section, these are of uncertain value. Subtalar arthrograms have been used in the workup of this condition. The normal subtalar joint will accept 3ml of contrast dye and will demonstrate multiple recesses and interdigitations within the joint capsule.[18] Under normal circumstances there is a small recess that projects anteriorly from the subtalar joint. The absence of this synovial recess has been associated with sinus tarsi syndrome. [0300] [0320]

The use of magnetic resonance imaging (MRI) in the evaluation of sinus tarsi syndrome has been investigated. The key MRI features have been reported as replacement of the normal fat signal intensity in the sinus tarsi with fluid, inflammatory tissues, or fibrosis. [0310] [0320] The inflammatory changes often will obscure the ligaments that normally are visualized in the sinus tarsi. Additional findings may include ligament injury, ganglion cysts, and degenerative joint disease.[33]

Nonoperative treatment

Injections of local anesthetic and steroid into the sinus tarsi may be both diagnostic and therapeutic. If the patient does not report even temporary relief following injection, then skepticism must be directed at a diagnosis of sinus tarsi syndrome. Some patients may report permanent resolution of their symptoms after a series of injections.[18] Surgery is indicated if pain recurs after a series of one to three injections.

Surgical treatment

Open and arthroscopic techniques are available. Open excision of the tissue filling the sinus tarsi has been reported to have good results. [0180] [0290] [0300] Typically a lateral oblique incision is made over the region of the sinus tarsi. The lateral branch of the superficial peroneal nerve is avoided. The inferior extensor retinaculum and the origin of the extensor digitorum brevis are reflected distally. The sinus tarsi is entered, and debridement is performed. Arthroscopic exploration ( Fig. 15-4 ) of the sinus tarsi for diagnosis and treatment has been described with good results, but often the postoperative diagnosis is changed from sinus tarsi syndrome to another more anatomic pathology, following direct visualization of the sinus tarsi area and the subtalar joint.[27]

A subtalar dislocation involves the dislocation of the talocalcaneal and talonavicular joints. With this injury there is no associated dislocation of the calcaneocuboid or tibiotalar joints. It was first described separately by DuFaurest[34] and Judcy[35] in 1811. Broca[36] later classified these injuries as medial, lateral, and posterior. In 1856, Malgaigne[37] revised this classification and added anterior subtalar dislocations as a specific entity. Frequency of the different subtypes of subtalar dislocations has been reported as 80% medial, 17% lateral, 2% posterior, and 1% anterior.[38]

Clinical presentation

These injuries typically are the result of high-energy mechanisms such as motor vehicle accidents or falls from a height. They also can result from a twisting athletic injury. In 1964, Grantham[39] used the term “basketball foot” to describe medial dislocations because four of the five patients in his series injured their foot playing basketball. Low- and high-energy mechanisms create two subtypes of subtalar dislocations. High-energy injuries are more likely to be open, more likely to be lateral, have a higher incidence of associated fracture, and have a worse long-term prognosis.[40]

Forced inversion of the foot results in a medial subtalar dislocation, whereas eversion causes a lateral dislocation. During medial dislocations, the sustentaculum tali serves as the fulcrum around which the foot rotates. With lateral dislocations, the foot rotates around the anterior process of the calcaneus.

Significant foot deformity is found in all patients with subtalar dislocation, although this may be somewhat obscured by swelling. Approximately 20% to 40% of subtalar dislocations are open. [0410] [0420] [0430] However, open injuries are unusual in the athlete.

Physical examination

The deformity is usually clinically obvious. With medial dislocations, the skin is tented over the lateral malleolus and the dorsolateral talar head. With lateral dislocations, the skin is tented over the prominent medial talar head and the medial malleolus. A thorough neurovascular examination should be performed, although ischemia of the foot is uncommon with these injuries, especially in the athlete. There is a risk of local ischemia to the soft tissues in the region of the tented skin if reduction is not prompt.

Radiographic evaluation

A standard three-view series of the foot and/or ankle (anterior/posterior, lateral, oblique) is obtained but can be suboptimal, given the distortion of normal anatomic relationships in the midfoot. The most helpful radiograph is the anterior-posterior view of the foot. The relationship between the talar head and navicular can best be evaluated. The relationship of the talar head to the concave proximal side of the navicular on this view normally is congruent on all views of the foot. On the lateral radiograph, the talar head lies superior to the navicular with medial subtalar dislocations. With lateral subtalar dislocations the opposite is true, and the talar head appears inferiorly displaced.

Associated fractures about the foot and ankle are common. These are better identified on postreduction radiographs. DeLee and Curtis[44] reported a 47% incidence of associated osteochondral fractures of the talonavicular or talocalcaneal joints in their series of 17 patients. Osteochondral fractures were more common with lateral subtalar dislocations in this series. Other series have reported an incidence of associated foot and ankle injuries of 64% to 88%. [0420] [0430]

Because of the difficulty in identifying associated fractures on plain radiographs, postreduction CT scans have been recommended as a means of identifying associated injuries.[44] Bohay and Manoli[45]reported four cases of patients who had normal films following reduction of subtalar dislocations. CT scans revealed intra-articular fractures in all four cases. The authors recommended CT scanning in all patients with normal radiographs following reduction of subtalar dislocations. Diagnosis is important because associated intra-articular fractures have been associated with a poor prognosis. [0430] [0440] [0460]

Nonoperative treatment

The majority of subtalar dislocations can be reduced using closed methods. Depending on the time from injury, reduction can be achieved with minimal sedation. Injuries left unreduced more than a few hours may require heavier sedation in the emergency department or operating room. The reduction process involves bending the knee to relax the gastrocnemius. Traction is applied to the heel and countertraction is applied to the thigh. As traction is being applied, the deformity is accentuated by inverting the foot for medial dislocations and everting it for lateral dislocations. The deformity then is reversed as direct pressure is placed over the prominent talar head to aid in reduction.

Following reduction, the foot is placed into a bulky splint. Slight eversion of the hindfoot in the splint will help to stabilize medial dislocations, and inversion will hold lateral dislocations. Plain radiographs then are obtained to verify reduction. A CT scan is recommended to rule out associated fractures. Dislocations without fractures are immobilized for 4 weeks to allow soft-tissue healing. Injuries with associated fractures will require a longer period of immobilization, typically in the range of 6 to 8 weeks. Following casting, a program of strengthening and range of motion exercises is initiated.

Surgical treatment

The indications for operative intervention are open injuries and inability to achieve a congruent reduction using closed methods. Lateral dislocations are more likely to require open reduction than medial dislocations. [0430] [0470] In their series of 25 patients, Bibbo et al.[43] reported that closed reduction was unsuccessful in 8 patients (32%). Four of these cases had identifiable soft-tissue interposition that blocked reduction. None of the patients with a low-energy mechanism of injury required an open reduction.

Blocks to reduction with medial dislocations may include buttonholing of the talar head through the extensor retinaculum or capsule of the talonavicular joint. [0480] [0490] There have been reports of the deep peroneal nerve interposition blocking reduction, as well.[48] Finally, the lateral navicular bone may impact into the medial talar head and thereby block reduction.[49] With lateral dislocations, impingement of the posterior tibial or flexor digitorum longus tendons, as well as impaction of the medial navicular bone onto the lateral talar head, may block reduction. [0490] [0500] [0510]

For open reduction of medial dislocations, a longitudinal anteromedial incision is made along the talar neck extending to the talar head. This allows access to the structures that have entangled the talar head. At the same time, inspection of impaction fractures of the articular surfaces can be carried out. For lateral dislocations, a more medial longitudinal incision is made over the prominent talar head. Interposed tendons are released and joint surfaces are inspected. Any tears found in the tendons should be repaired.

Tarsal Coalition

Tarsal coalition involves a congenital union between two or more tarsal bones. This union may be bony, cartilaginous, or fibrous in nature. The two most common locations for coalition are at the talocalcaneal and calcaneonavicular joints. These locations account for approximately 90% of all coalitions.[52] Less commonly, coalitions have been described at the talonavicular, calcaneocuboid, navicular cuneiform, and cuboid navicular joints.

Previously it had been suggested that the etiology of tarsal coalition involved the incorporation of accessory ossicles into adjacent tarsal bones.[53] In 1955, Harris[54] performed microscopic dissection of fetal hindfeet and demonstrated a failure of mesenchymal separation. This failure of segmentation has become the most widely accepted theory regarding the etiology of this disorder. It generally is described as an autosomally dominant disorder with incomplete penetrance. [0550] [0560]

The incidence of tarsal coalition has been estimated to be less than 1%.[57] The incidence probably was underestimated before the use of CT scans. Further confounding the incidence is the asymptomatic nature of a large percentage of coalitions. In 1974, Leonard[58] studied the first-degree relatives of 31 patients with tarsal coalition. He found that 39% of the first-degree relatives had coalitions on radiographs, but all were asymptomatic. Approximately 50% of coalitions are bilateral, with calcaneonavicular coalitions more likely to occur bilaterally. [0570] [0590]

Clinical presentation

Patients with this condition often are asymptomatic until ossification of the fibrous or cartilaginous coalition occurs. Before this time, some degree of motion is preserved at the affected joint. Once the coalition ossifies, the motion at the affected joint is lost and symptoms may arise. The timing of this ossification may vary, depending on the location of the coalition. Patients with calcaneonavicular coalitions may become symptomatic earlier (age 8-12 years) than patients with talocalcaneal coalitions (age 12-16 years).[60]

Patients with tarsal coalition can present with pain, stiffness, and/or a deterioration of athletic performance. Increased stresses are placed on surrounding structures as motion in the hindfoot is restricted, and this may lead to pain. Although a planovalgus position of the foot has been classically described, feet with normal arches or even a cavovarus deformity may contain a coalition.[61] The symptoms are often low grade and not severe enough to prompt a visit to the doctor until a traumatic event causes a flare-up of pain.

Recurrent ankle sprains often are described in athletes with tarsal coalitions.[62] Forced motion beyond that which can be accommodated by the abnormal joints may lead to partial or complete ligamentous injuries. The abnormal joints are unable to dissipate the forces generated by athletic activities, and therefore the increased stresses are transferred to the ligamentous structures.

Physical examination

Patients tend to have a rigid flatfoot involving heel valgus, loss of the midfoot arch, and abduction of the forefoot.

Pearl

This should be differentiated from an asymptomatic flexible flatfoot, in which heel varus and medial arch is restored with single-foot and double-foot heel rise.

The degree of the deformity can be quite variable. Talocalcaneal coalitions are associated with a more severe hindfoot valgus deformity than coalitions at other sites.[63] Talocalcaneal coalitions typically eliminate motion of the subtalar joint.

Pearl

Calcaneonavicular coalitions may cause only a partial reduction of subtalar motion, with more restriction of Chopart's motion.

The patient may be tender about the hindfoot/midfoot, depending on the location of the coalition. Calcaneonavicular coalitions often cause anterolateral tenderness directly over the joint. Talocalcaneal coalitions may cause lateral tenderness over the sinus tarsi and peroneal tendons, as well as medially just anterior to the medial malleolus. A bony eminence from talocalcaneal coalitions has been described as a cause of tarsal tunnel symptoms. In one series, 30% of patients with tarsal tunnel syndrome were found to have an eminence from a talocalcaneal coalitions as a source of the symptoms.[64]

Peroneal spasm may or may not be present. This finding has been suggested as part of the classic presentation of this disorder; however, it is found only in the minority of cases. [0570] [0650]

Radiographic evaluation

Initial evaluation of the patient should include weight-bearing anterior-posterior, lateral, and oblique radiographs of the affected foot. An axial heel view should be added to these three views of the foot so that the talocalcaneal joint can be inspected. These may identify the presence of a coalition and degenerative changes in the surrounding joints. A calcaneonavicular bar is best seen on the 45-degree medial oblique view. A lateral x-ray may show the “anteater nose,” a projection from the anterior process of the calcaneus to the navicular ( Fig. 15-5, A ) that is a sign of the calcaneonavicular coalition, as described by Oestreich et al.[66] The axial heel view is the best plain radiograph for diagnosing coalitions of the middle facet of the subtalar joint. Secondary signs of a talocalcaneal coalition also may be detected on the lateral view. These include narrowing of the posterior facet of the subtalar joint, blurriness of the middle facet of the subtalar joint, beaking of the dorsal head of the talus, and rounding of the lateral process of the talus.[67]

CT has been established as the gold standard study for the identification of talocalcaneal coalitions. [0680] [0690] A CT scan ( Fig. 15-5, B ) allows one to identify the coalition, determine the extent of joint involvement, and assess any areas of surrounding degenerative changes. It can be particularly useful for preoperative planning and determining whether a coalition is resectable. It also may be used postoperatively to assess the completeness of resection, progressive degenerative changes, and recurrence of the coalition.

Less commonly, MRI has been used in the workup of tarsal coalitions ( Fig. 15-5, C ). It may better identify nonosseous coalitions.[70] The surrounding joints and soft tissues can be evaluated, as well. A radionuclide bone scan also may be useful in the diagnosis of the symptomatic patient with suspected tarsal coalition, particularly as a screening procedure.[71] This test can be positive when the patient is symptomatic. Accumulation of the radionuclide most likely is the result of increased stresses at the surrounding joints or within the coalition itself.

Nonoperative treatment

Typically a trial of nonoperative management is indicated in the treatment of tarsal coalitions. A study by Jayakumar and Cowell[72] in 1977 found that one third of their patients responded favorably to conservative treatment. When the diagnosis is made in the adolescent who is a competitive athlete, then definitive treatment on a more expedient basis may be appropriate. In this manner, the time off from competition may be reduced. Morgan and Crawford[73] looked at 12 adolescent athletes with coalitions (8 calcaneonavicular and 4 talocalcaneal). Nonoperative treatment was successful in none of the patients, and 8 of the 12 elected to undergo surgery.

The usual regimen of nonoperative management for patients with mild symptoms includes anti-inflammatory medications and orthotics. For more severe symptoms, patients may undergo a trial of a short-leg walking cast for a period of 6 weeks. If the patient responds favorably to immobilization, then orthoses are used. The patient is considered to have failed nonoperative treatment if pain persists after two cast applications.

Surgical treatment

The most common procedures performed for tarsal coalition include resection of the coalition, selected arthrodesis, and triple arthrodesis. Previous reports have examined resection of tarsal coalitions in adolescent athletes. In Morgan and Crawford's[73] review of 12 adolescent athletes, they reported their results in 8 athletes who underwent resection of tarsal coalitions. They found that 5 out of 6 athletes who had calcaneonavicular bars were able to return to play. Both athletes with talocalcaneal bars were also able to return to play following resection. Elkus[74] examined 15 feet with calcaneonavicular coalitions and 8 with talocalcaneal coalitions in a population of young athletes. All patients underwent resection of their coalitions with or without soft-tissue interposition. The majority of the patients had relief from pain (no numbers reported) with variable return of subtalar motion. The author did note that all 8 cases of talocalcaneal bar resection had improvement in motion, had decreased pain, and were able to return to athletic activity.

Calcaneonavicular Coalitions

The accepted treatment for calcaneonavicular coalitions is resection with soft-tissue interposition unless degenerative changes are present in the subtalar or midtarsal joints. Although talar beaking previously was thought to be evidence of degenerative changes, it is not a contraindication to resection.[75] One contraindication to resection is the presence of a concomitant talocalcaneal coalition. Generally the bar should be resected during adolescence, but resection of bars in the adult population has been shown to be beneficial, as well.[76] There is evidence that results are improved after resection of cartilaginous coalitions rather than bony bars.[77]

The reported outcomes following surgical excision of the coalition have been variable. Cohen et al.[76] in 1996 reviewed their results when resecting coalitions in adults. They examined 12 patients, 77% of whom displayed degenerative changes before resection. All but two of the patients reported subjective relief of the preoperative symptoms. Gonzalez and Kumar[77] reported on 75 feet in 48 patients with calcaneonavicular coalitions. Their results with resection and interposition with the extensor digitorum brevis muscle was good or excellent in 77% of the patients. The authors noted that their best results were in patients who had a cartilaginous coalition and who were younger than 16 years. In contrast, Andreasen[78] reported results of 31 bar resections that were examined 10 to 22 years following surgery. He found 30% of the patients had mild pain and 26% had severe pain. A recurrence of the bar was seen in 67% of patients despite the use of interpositional muscle, and 96% of feet had osteoarthritic changes. Six patients required triple arthrodesis.

Technique of resection of calcaneonavicular coalition

A 5- to 6-cm curvilinear incision is made just below the fibula, exposing the fascia overlying the extensor digitorum brevis. One should avoid branches of the superficial peroneal and sural nerves. The extensor digitorum brevis is reflected distally, exposing the calcaneocuboid joint, sinus tarsi, and calcaneonavicular coalition. The coalition is resected in parallel cuts from each surface, avoiding convergence. The hindfoot is mobilized to test for adequate subtalar motion. Bone wax is generously packed into the bony surfaces. The extensor digitorum brevis is placed into the resection site and sutured in place. Closure is done in layers (Figs. 15-6 and 15-7 [0060] [0070]).

Figure 15-6 Drawing demonstrating excision of calcaneonavicular coalition and interposition of extensor brevis. (A) Skin incision. (B) Exposure of the extensor brevis. (C) Reflection of the extensor brevis forward demonstrates the area of coalition. (D) Demonstration of the area of coalition to be resected. (E) Interposition of the extensor brevis muscles. From Mann RA, Coughlin MJ, editors: Surgery of the foot and ankle, ed 6, St Louis, 1992, CV Mosby. Used by permission.

Resection of the coalition also is the treatment of choice in patients with symptomatic talocalcaneal coalitions. Skeletally immature patients with smaller bars and no evidence of degenerative changes in the subtalar joint are most likely to benefit from resection.[69] Contraindications to resection include patients with rigid flatfeet or degenerative changes of the subtalar and transverse tarsal joints. These patients are better served with a subtalar or triple arthrodesis. In carefully selected patients, generally 80% to 90% will report satisfactory results following a resection. [0790] [0800] [0810]

The decision whether to resect the coalition or perform a fusion may be influenced by the size of the bar. Some feel that involvement of more than one half of the joint will preclude a successful resection.[81] Wilde et al.[82] reported unsatisfactory outcomes with middle coalition resection and fat interposition in the presence of middle facet coalition area greater than 50% of the area of the posterior facet. On the other hand, Kumar et al.[80] did not find a correlation between the extent of middle facet coalition and the postoperative results in 18 feet on which resection was performed.

Technique of resection of talocalcaneal coalition

A 6- to 7-cm linear incision is made just below the medial malleolus, just above the sustentaculum tali (Figs. 15-8, A and 15-9, A [0080] [0090]). Tenotomy scissors are used to dissect and identify the posterior tibial tendon, flexor digitorum longus, and tibial neurovascular bundle. The middle facet lies just under the flexor digitorum longus (FDL), often covered by minimal periosteum. The middle facet with coalition is identified and dissected, showing the extent of the coalition (Figs. 15-8, C and 15-9, B [0080] [0090]). Once the corners of the coalition are identified, excision is done using small straight osteotomes and rongeurs. The excised surfaces should be parallel to prevent contact and potential osseous fusion (Figs. 15-8, D and 15-9, C [0080] [0090]). Bone wax is placed generously on the excised surfaces, and Gelfoam is interposed. Other authors interpose fat from the surrounding tissue.[76] Closure of the FDL sheath is included in the layered closure.

Figure 15-8 Excision of talocalcaneal coalition. (A) Skin incision. (B) Reflection of structures dorsally and plantarward to expose the area of coalition. (C) Outlining the coalition with needles. (D) Postexcision appearance of the coalition. From Mann RA, Coughlin MJ, editors: Surgery of the foot and ankle, ed 6, St Louis, 1992, CV Mosby. Used by permission.